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Full-Text Articles in Physical Sciences and Mathematics

Radial Basis Function Generated Finite Differences For The Nonlinear Schrodinger Equation, Justin Ng Mar 2018

Radial Basis Function Generated Finite Differences For The Nonlinear Schrodinger Equation, Justin Ng

Theses and Dissertations

Solutions to the one-dimensional and two-dimensional nonlinear Schrodinger (NLS) equation are obtained numerically using methods based on radial basis functions (RBFs). Periodic boundary conditions are enforced with a non-periodic initial condition over varying domain sizes. The spatial structure of the solutions is represented using RBFs while several explicit and implicit iterative methods for solving ordinary differential equations (ODEs) are used in temporal discretization for the approximate solutions to the NLS equation. Splitting schemes, integration factors and hyperviscosity are used to stabilize the time-stepping schemes and are compared with one another in terms of computational efficiency and accuracy. This thesis shows …


W1,P Regularity Of Eigenfunctions For The Mixed Problem With Nonhomogeneous Neumann Data, Kohei Miyazaki Jan 2018

W1,P Regularity Of Eigenfunctions For The Mixed Problem With Nonhomogeneous Neumann Data, Kohei Miyazaki

Murray State Theses and Dissertations

We consider an eigenvalue problem with a mixed boundary condition, where a second-order differential operator is given in divergence form and satisfies a uniform ellipticity condition. We show that if a function u in the Sobolev space W1,pD is a weak solution to the eigenvalue problem, then u also belongs to W1,pD for some p>2. To do so, we show a reverse Hölder inequality for the gradient of u. The decomposition of the boundary is assumed to be such that we get both Poincaré and Sobolev-type inequalities up to the boundary.


Comparing Two Thickened Cycles: A Generalization Of Spectral Inequalities, Hannah E. Pieper Jan 2018

Comparing Two Thickened Cycles: A Generalization Of Spectral Inequalities, Hannah E. Pieper

Honors Papers

Motivated by an effort to simplify the Watts-Strogatz model for small-world networks, we generalize a theorem concerning interlacing inequalities for the eigenvalues of the normalized Laplacians of two graphs differing by a single edge. Our generalization allows weighted edges and certain instances of self loops. These inequalities were first proved by Chen et. al in [2] but our argument generalizes the simplified argument given by Li in [8].